1. Field of the Invention
This invention relates to a high speed machine rotor and, more particularly, to a structure facilitating precision machine winding of the rotor and a method of producing the same.
2. Background Art
Manufacturers of high speed generator rotors strive towards winding the rotor uniformly, rigidly and compactly so that a lightweight and balanced structure results. Often the rotor is hand wound. Inconsistent tension on and placement of hand wound turns is inevitable. As a result, the completed rotors may vary in shape and weight from one to the other. With the turns loosely wound, the available space is not efficiently utilized. Further, because the final shape of the hand wound rotor is unpredictable, the rotor encasement must be made large enough to handle the more loosely wound, and therefore larger, rotors. This accommodation, added to the installation clearances, makes the encasement substantially larger than desirable. The weight, amount of material required and the attendant manufacturing costs of the rotor are thereby proportionately increased. The electrical resistance of the coil is also increased with a loosely wound rotor.
An additional drawback with the hand wound prior art structures is that the field windings may shift on the core. The first, base layer is maintained on the core primarily by frictional forces developed by the combined effect of the tension on the wire and the pressure from progressively developed layers. This shifting and the weight imbalance resulting from loosely wound turns combine to cause detrimental centrifugal effects.
Rotors prewound by machine present many of the same problems associated with hand winding. The uniformity of the winding pattern and thus the predictability of the final rotor dimension cannot be assured. Further, clearance must be provided with the completed winding to allow placement over the rotor core, and adds to the size of the rotor. The resulting structure has numerous other of the drawbacks of the hand wound rotor, namely a lack of balance and a greater weight than is desirable. A still further drawback with prewound rotors is the requirement of additional manufacturing steps. The rotor winding must be removed from a drum or the like and mounted fixedly on the rotor core.
The present invention is specifically directed to overcoming the problems enumerated above.